Hair morphology

1. SEMEY MEDICAL UNIVERSITY

STUDENT INDEPENDENT WORK
HISTOLOGY OF HAIR AND NAIL
SUBMITTED BY : PRAJAPATI VENKATESH
SUBMITTED TO : MADAM SALTANAT

2. PLAN:-

PLAN:• Morphology and Structure of Human Hair
• Parts of hair
• Regions of hair
• The cuticle
• The cortex
• The medulla
• Types of hair
• The vallus:• The terminal:• The intermediate:-
• Changes of hair

3.

4. Parts of hair:-

Parts of hair: The shaft
The root or follicle
• The hair is formed by cells of the dermal papilla at the
base of the follicle.
• Follicles are formed during the growth of the foetus, no
new follicles are formed post natally.
• The major function of hair is thermal insulation.

5. Regions of hair

6. The cuticle:-

The cuticle:• the outer region – encircles the cortex, and is made
of 5 to 15 overlapping layers. Externally is seen as a
series of uneven edges, which can be forced
outwards by combing or friction. There are gaps
between these layers, permitting small molecules to
enter or leave the cortex

7. The cortex:-

The cortex:the middle region – which has a fibrous
appearance, long strands of fibers run along the
length of the hair, interweaving so as to form a
structure of great strength and elasticity.

8. The medulla:-

The medulla:• a central canal. The cells are nucleated near the
papilla, but the cell contents are lost they progress
upwards. Many hairs have no medulla.

9.

10. Types of hair

11. The vallus:-

The vallus:• are short, fine, soft, usually non
pigmented and unmedullated

12. The terminal:-

The terminal:• are large, darkly pigmented and often
medullated 90% of the hairs on the
chest, trunk, shoulders, legs and arms
of men are terminal, only 45% on
women.

13. The intermediate:-

The intermediate:• occur on the scalp, their morphology
falls between those of terminal and
vellus and they are medullated and
contain moderate amount of pigment.

14. Changes of hair:-

Changes of hair:• Anagen phase: The hair grows at a rate of about
1cm/ month, during which the old hair is shed and
new growth begins. Of 100,000 – 150,000 scalp hairs
on human adult, regardless of sex, 90% are in the
anagen phase
• Catagen phase: 5% resting phase
• Telogen Phase: 5%